Pulsed electrodeposition offers the potential for superior control of deposit properties because of the additional control variables available. However, the optimization of pulsed deposition processes is a challenge because of the complexity created by these additional variables. For example, the tendecy of electroforms to acquire irregularities such as dendritic growths or other morphological instabilities, creates the need for methods to control these undesirable phenomena. One such method is periodic reverse pulses. The optimization of periodic reverse processes is not simple, and can lead to local solutions that do not optimize all properties simultaneously. One method for global optimization that might, for example, control surface irregularities on several size scales, uses a periodic reverse design based on a fractal time series. This incorporates deplating pulses of several lengths within one self-similar waveform. The properties of fractals permit the control of highly complex designs with a small number of input variables. The creation of such waveforms, their properties, and their use in a lead-plating process are described. Speculation on the potential for further application of this method is offered.
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